Well Early Access only has the first 4 levels worth of spells.

About 6-8 skills per tree...

I honestly have no idea. It is very possible there are LESS spells as there will likely be a nuke taken to the Summons, shields, and avatars.

Then there are skills that have been folded into each other.

-First Aid is combined with Doctor and Cure Poison.
-Fortitude is likewise combined with a few other skills

I THINK this game will have more, I know they shown us ALL the skill icons, so we could count those.